1. Field of the Invention
The present invention relates to a developing apparatus and method for display panels, and more particularly to a developing apparatus and method suitable for organic electroluminescent (OEL) display panels.
2. Description of Related Art
Recently, the OEL displays become a focus of flat panel display devices market because of several advantages such as self-light-emitting, high brightness, high contrast, wide viewing angle, low driving voltage, fast response and compact structure. However, even samples of OEL displays fabricated in laboratories can achieve acceptable results, many problems in practical mass production of these OEL displays still need to be overcome.
A conventional passive OEL display panel includes a plurality of parallel stripes of indium tin oxide (ITO) functioning as anodes, a plurality of parallel isolation walls of photoresist which are frequently perpendicular to the stripes of anodes, at least a layer of an organic electroluminescent functional medium locating between any two adjacent isolation walls of photo resist, and a plurality of stripes of cathodes formed on the layer of organic electroluminescent functional medium. In most cases, the patterns of the anodes and pixel areas are further defined by a defining layer through developing, etching and stripping an exposed photo resist layer coated on said panels.
Although many anodes, cathodes and the isolation walls of the passive OEL display are formed through photolithography. However, as the size of OEL display increases, the conventional developing used in the manufacturing process cannot be applied well in the manufacturing process for medium-sized or large-sized OEL display panels. For the conventional development technology used in fabricating integrated circuits, the silicon substrate is mounted on spin chuck, the developing solution and water is dispensed from nozzles respectively as the silicon substrate is spun in a high speed. The developed silicon substrate is further dried as the developing quenches. But as the size of the display increases, the glass substrate of the display weighs much heavier than the conventional silicon wafer. Therefore, the conventional spin chuck designed for the silicon wafer cannot afford to sustain the weight of the glass substrate and the centrifugal force caused from the high-speed spin of the large-sized OEL panels. Hence, incomplete development accompanied with residual photo resist significantly reduces the yields of OEL display devices. Recently, the developing of OEL panels is suggested to go through a batch process to avoid the above problems. In the proposed batch process, the panel substrate of the display is immersed in a separate developing tank from rinsing bath. This batch process for developing OEL panel substrates cannot be achieved in a continuous manner since individual operators are required for the labor work to take out each display panel and re-load the same onto another machine. Hence, the processing time of development are inevitably prolonged. The batch processing still fails to exempt from the disadvantage for mass production and inconvenient for manufacturing large-sized display panel. In addition, labor work usually causes unexpected delaying or damages in the delivery of the OEL display panels. Hence, the time and quality for developing OEL panels cannot be accurately controlled through the conventional developing apparatus.
On the other hand, the known developing apparatus, in addition to the spin-coating developing apparatus, requires expensive and complicated sensors, controlling systems, reciprocating motion mechanisms and complicated controlling programs. The cost for purchasing these apparatus is very high. The maintenance of these equipments is also troublesome since complicate mechanism and complicated controlling system is needed. By the way, in most cases, the individual units in these apparatus remain in an idled situation for waiting the developed panels in some particular processing steps. Therefore, the efficiency for the application used for developing OEL panels is low. There is a need for providing a developing apparatus that is compact, easily to be maintained, and operable efficiently to reduce the running cost for the OEL display panels so as to meet the requirement for mass production and solve the problems in the developing process of the large-sized OEL display panels.
In other words, it is desirable to provide an improved apparatus for OEL display panels to mitigate and/or obviate the aforementioned problems.